The field of the disclosure relates generally to resolution of digital images, and more specifically, to methods and systems for improving resolution of a digitally stabilized image.
When collecting images of objects, such as a target, the sharpness of the picture is limited by one or more of the quality of the optics, pixel number, pixel size, and how densely the pixels are packed. With a larger pixel size, images are under sampled and the image quality is adversely affected. Generally, the smaller the pixel size, the clearer the image.
Image collecting devices that incorporate infrared focal planes, for example, those used in spacecraft and other air vehicles, tend to suffer from a low number of pixels and a relatively large pixel size, simply due to the current state of the art of fabricating infrared focal planes. In other words, the technology is not available, or is prohibitively expensive, to fabricate an infrared focal plane that incorporates a large number of pixels. Generally, for a high frame rate, image recording device that operates in the long wave infrared range, the current state of the art is in the range of about 500 by 500 pixels, with a pixel size in the range of about fifteen to about forty microns.
There remains an unfulfilled need to increase image resolution in a long wave infrared system in order to discern between targets that are close together. Such targets are sometimes referred to as closely spaced objects (CSOs). Prior attempts to increase such image resolution have included incorporation of larger apertures and smaller focal planes. However, incorporation of such solutions is limited by the current state of the art in this technology area and therefore ignores spatial sampling issues. One result is an array that is mapped with pixels that are as large as possible, into an equal sized array, thus achieving no-better (or worse) spatial resolution than just the focal plane of a focal plane array. Smaller focal planes, which include the incorporation of smaller pixels, have corresponding smaller fields of view, which may be a tactical disadvantage. In any event, reduction in pixel size is limited by the state of art of manufacturing, and same-sized arrays that incorporate smaller pixels require processing capability that is proportional to the number of pixels within an area.
Other attempts to increase image resolution include statistical image post-processing techniques as well as other image-processing techniques. Statistical post processing ignores the possibility of a priori knowledge of camera position and “guesses” the position statistically, inducing extra noise into the process. Statistical image post-processing does not take advantage of any knowledge of motion and there is no capability to take quick snapshots that avoid blurring, due to motion or atmosphere. Furthermore, data with low signal-to-background ratios is generally not usable. In summary, existing solutions cannot maximize spatial resolution and signal to noise ratio, or do not get the best performance possible out of the focal plane/camera system.